Power supplies including shielded multilayer power transmission boards

ABSTRACT

A power supply comprises a main circuit board and a multilayer power transmission board electrically coupled to the main circuit board. The multilayer board includes a conductive neutral layer having an inner side, a conductive line layer having an inner side facing the inner side of the conductive neutral layer, and a dielectric medium positioned between the conductive neutral layer and the conductive line layer. The power supply also comprises a first conductive outer layer positioned adjacently to an outer side of the conductive neutral layer, a second conductive outer layer positioned adjacently to an outer side of the conductive line layer, and a conductive plating material positioned within a slot formed in the multilayer power transmission board and covering an interior portion of the multilayer power transmission board facing the slot. The conductive plating material electrically couples the first and second conductive outer layers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. applicationSer. No. 15/951,810 filed Apr. 12, 2018, which claims the benefit of andpriority to U.S. Provisional Application No. 62/485,097 filed Apr. 13,2017. The entire disclosures of the above applications are incorporatedherein by reference.

TECHNICAL FIELD

The present disclosure relates to powers supplies including shieldedmultilayer power transmission boards.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Electrical power supplies commonly include main circuit boards forsupporting various electrical components. In some instances, the powersupplies include AC jumper boards having a neutral layer and a hot layerfor moving AC power between different areas of the main circuit boards.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

According to one aspect of the present disclosure, a power supplycomprises a main circuit board and a multilayer power transmission boardelectrically coupled to the main circuit board. The multilayer boardincludes a conductive neutral layer having an inner side, a conductiveline layer having an inner side facing the inner side of the conductiveneutral layer, and a dielectric medium positioned between the conductiveneutral layer and the conductive line layer. The power supply alsocomprises a first conductive outer layer positioned adjacently to anouter side of the conductive neutral layer, a second conductive outerlayer positioned adjacently to an outer side of the conductive linelayer, and a conductive plating material positioned within a slot formedin the multilayer power transmission board and covering an interiorportion of the multilayer power transmission board facing the slot. Theconductive plating material electrically couples the first and secondconductive outer layers.

According to another aspect of the present disclosure, a power assemblycomprises a multilayer power transmission board comprising a pair ofconductive outer layers, a conductive neutral layer positioned betweenthe pair of conductive outer layers and having an inner side and anouter side, and a conductive line layer positioned between the pair ofconductive outer layers and having an inner side facing the inner sideof the conductive neutral layer and having an outer side. The powerassembly also comprises a dielectric medium positioned between theconductive neutral layer and the conductive line layer and comprises aconductive material electrically coupling the pair of conductive outerlayers together and plated on an interior portion of the multilayerpower transmission board within a slot formed in the multilayer powertransmission board.

According to another aspect of the present disclosure, a method ofmanufacturing a power supply including a main circuit board and a powertransmission multilayer board, the power transmission multilayer boardincluding a conductive neutral layer having an inner side facing theinner side of the conductive line layer and having an outer side, aconductive line layer having an inner side and an outer side, adielectric medium positioned between the conductive neutral layer andthe conductive line layer, a first conductive ground layer positionedadjacently to the outer side of the conductive neutral layer, and asecond conductive ground layer positioned adjacently to the outer sideof the conductive line layer. The method comprises forming at least twoslots in the power transmission multilayer board to expose at least aportion of an interior of the power transmission multilayer board,plating with a conductive material the exposed interior of the powertransmission multilayer board so that the conductive material is incontact with the two conductive ground layers, and electrically couplingthe power transmission multilayer board and the main circuit board.

Further aspects and areas of applicability will become apparent from thedescription provided herein. It should be understood that variousaspects of this disclosure may be implemented individually or incombination with one or more other aspects. It should also be understoodthat the description and specific examples herein are intended forpurposes of illustration only and are not intended to limit the scope ofthe present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a block diagram of a power supply including a main circuitboard and a multilayer power transmission board for transmitting powerfrom one area of the main circuit board to another area of the maincircuit board according to one example embodiment of the presentdisclosure.

FIG. 2A is a block diagram an AC multilayer power transmission boardemployable in the power supply of FIG. 1, according to another exampleembodiment.

FIG. 2B is the AC multilayer power transmission board of FIG. 2A withX-capacitors, according to yet another example embodiment.

FIG. 3 is a block diagram a multilayer power transmission boardemployable in the power supply of FIG. 1, according to another exampleembodiment.

FIG. 4A is a top view of an outer conductive layer for a multilayerpower transmission board according to yet another example embodiment.

FIG. 4B is a top view of another outer conductive layer for themultilayer power transmission board of FIG. 4A, according to anotherexample embodiment.

FIG. 4C is a top view of an inner conductive layer for the multilayerpower transmission board of FIG. 4A, according to yet another exampleembodiment.

FIG. 5 is an isometric front view of a power supply including a maincircuit board and a multilayer power transmission board according toanother example embodiment.

FIG. 6 is an isometric rear view of the power supply of FIG. 5.

FIG. 7 is an enlarged portion of the power supply of FIG. 6.

FIG. 8A is an isometric top view of a portion of a multilayer powertransmission board having plated slots forming outer conductive layersof the board, according to yet another example embodiment.

FIG. 8B is an isometric top view of the multilayer board of FIG. 8A witha portion of the board removed to form the outer conductive layers,according to another example embodiment.

FIG. 9 is a top view of a portion of a multilayer power transmissionboard having conductive vias on opposing sides of the board according toyet another example embodiment.

FIG. 10 is a graph of conducted EMI in a power supply having amultilayer board without outer conductive ground layers.

FIG. 11 is a graph of radiated EMI in the power supply of FIG. 10.

FIG. 12 is a graph of conducted EMI in the power supply of FIGS. 5-7with its multilayer board having outer conductive ground layers.

FIG. 13 is a graph of radiated EMI in the power supply of FIGS. 5-7 withits multilayer board having outer conductive ground layers.

Corresponding reference numerals indicate corresponding parts and/orfeatures throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

A power supply according to one example embodiment of the presentdisclosure is illustrated in FIG. 1 and indicated generally by referencenumber 100. As shown in FIG. 1, the power supply 100 includes a maincircuit board 102 and a multilayer power transmission board 104. Themain circuit board 102 includes a power input connector 106 having atleast two power connections A, B, and a power output connector 108. Asfurther explained below, the multilayer power transmission board 104includes one or more electrically conductive layers for transmittingpower from one area of the main circuit board 102 to another area of themain circuit board 102.

The power connectors 106, 108 may be AC power connectors or DC powerconnectors. If the power input connector 106 is an AC power inputconnector, the power connection A may be considered a neutral powerconnection and the power connection B may be considered a line (e.g. ahot) power connection, or vice versa. Alternatively, the power inputconnector 106 may be a DC power input connector. In that case, the powerconnection A may be considered a positive power connection and the powerconnection B may be considered a reference (e.g., ground) powerconnection, or vice versa. In other embodiments, the power inputconnector 106 may include one or more other connections for ground,additional neutral and/or line connections, positive DC connections,data/signal connections, etc.

Additionally, the power output connector 108 may include variousconnections such as one or more AC neutral connections, AC lineconnections, AC and/or DC ground connections, hot DC connections,data/signal connections, etc. Additionally, the power output connector108 may include the same or a different number of power connections asthe power input connector 106.

As shown in FIG. 1, the power connectors 106, 108 are adjacent to eachother. For example, and as shown in FIG. 1, the power connectors 106,108 are positioned adjacent one side surface, edge, etc. of the maincircuit board 102. In other embodiments, one connector may be near oneedge of the main circuit board 102 and the other connector may be nearan opposing edge of the main circuit board 102.

The main circuit board 102 (and any other main circuit boards disclosedherein) may be any suitable circuit board. For example, the main circuitboard 102 may be a printed circuit board (PCB), etc. Likewise, themultilayer power transmission board 104 (and any other multilayer boarddisclosed herein) may be any suitable power transmission board. Forexample, the multilayer board 104 may be a circuit board (e.g., a PCB,etc.) and/or another suitable board for transmitting power.

Additionally, although not shown in FIG. 1, the main circuit board 102may include one or more electrical components disposed on one or moresurfaces of the main circuit board 102. For example, one or morefilters, capacitors, inductors, transformers, power switches,rectification circuits, control circuits (e.g., control circuitintegrated circuits, etc.), etc. may be coupled to a top surface and/ora bottom surface of the main circuit board 102. The electricalcomponents may be positioned on the main circuit board 102 and adjacentto the multilayer board 104. In some examples, the electrical componentsmay be electrically coupled to one or more electrically conductivelayers of the multilayer board 104.

Power converter circuitry (e.g., collectively forming one or more powerconverters) may be electrically coupled between the power inputconnector 106 and the power output connector 108. For example, theelectrical components mentioned above (e.g., the capacitors, theinductors, the transformers, the power switches, etc.) and/or othersuitable electrical components may form the power converter(s). Thepower converter(s) may be positioned adjacent to the multilayer board104, and electrically coupled to one or more electrically conductivelayers of the multilayer board 104. The power converter(s) may includean AC/DC power converter, a DC/DC converter, etc., and have one or moresuitable topologies (e.g., buck converter topologies, boost convertertopologies, flyback converter topologies, forward converter topologiesetc.).

The multilayer board 104 may include one or more outer conductivelayers. For example, the outer conductive layers may form an outerperimeter of the multilayer board 104. In other examples, a dielectricmedium may be placed on the exterior facing side of the outer conductivelayers. In either example, the conductive layers may substantiallysurround an interior portion of the multilayer board 104 to provideshielding for internal layers of the multilayer board 104.

For example, the outer conductive layers may shield noise innerconductive layers of the multilayer board 104 from electromagneticfields generated by electrical components on the main circuit board 102.The noise may include, for example, electromagnetic interference (EMI)(sometimes referred to as radio frequency interference (RFI)), etc. Assuch, the conductive layers may help prevent noise from interfering withthe inner conductive power layers of the multilayer board 104, the inputat the input connector 106, etc. Thus, by shielding at least some noisein the power supply 100, other filters (e.g., controller area network(CAN) filters, etc.) may not be required in the power supply 100. Inturn, valuable circuit board space may be saved and costs may bereduced.

In some embodiments, one or more of the outer layers may be grounded.For example, the outer layers may be electrically coupled to ground(e.g., a ground trace, etc.) on the main circuit board 102 and/or atanother suitable location. By grounding one or more of the outer layers,the board 104 may provide improved shielding performance as compared toboards having ungrounded outer layers.

As explained above, the multilayer power transmission board 104transmits power from one area of the main circuit board 102 to anotherarea of the main circuit board 102. For example, the multilayer board104 may transmit power from one side of the main circuit board 102 tothe opposing side of the main circuit board 102. This configuration mayfree up valuable space on the main circuit board 102 for othercomponents, reduce the size of the circuit board, etc.

The AC or DC power may be transmitted between different areas of themain circuit board 102 by one or more conductive layers in themultilayer board 104. For example, the multilayer power transmissionboard 104 of FIG. 1 includes one or more other electrically conductivelayers (not shown) located between the outer conductive layers. Theseconductive layers may include, for example, a conductive neutral layerand a conductive line layer for transmitting AC power from one area ofthe main circuit board 102 to another area of the main circuit board102. In other embodiments, the conductive layers may include, forexample, a positive conductive layer and a reference conductive layerfor transmitting DC power from one area of the main circuit board 102 toanother area of the main circuit board 102.

For example, FIGS. 2A and 3 illustrate cross sectional views of powertransmission multilayer boards 200, 300, respectively. Either of themultilayer boards 200, 300 and/or another suitable board may be used forthe multilayer power transmission board 104 of FIG. 1.

As shown in FIG. 2A, the multilayer power transmission board 200includes two outer electrically conductive layers 202, 204, four innerelectrically conductive layers 206, 208, 210, 212 positioned between theouter layers 202, 204, and a dielectric medium 214 positioned betweeneach of the conductive layers 202, 204, 206, 208, 210, 212. Thedielectric medium 214 electrically isolates the conductive layers 202,204, 206, 208, 210, 212 from each other.

Additionally, and as shown in FIG. 2A, the dielectric medium 214 extendsaround an exterior side of the outer layers 202, 204. Alternatively, thedielectric medium 214 may not extend around the exterior side of theouter layers 202, 204, may extend around only a portion of the exteriorside of the outer layer 202 and/or the outer layer 204, etc.

When the board 200 is used in the power supply 100 of FIG. 1, theconductive layers 206, 208 may be two AC neutral conductors, and theconductive layers 210, 212 may be two AC line conductors (e.g., hotconductors). In such examples, the conductive neutral layers 206, 208are electrically coupled to the connection designated as the neutralconnection (e.g., the connection A) of the power input connector 106 ofFIG. 1, and the conductive line layers 210, 212 are electrically coupledto the connection designated as the line connection (e.g., theconnection B) of the power input connector 106 of FIG. 1.

In the particular example of FIG. 2B, the conductive neutral layers 206,208 and the conductive line layers 210, 212 are positioned in analternating configuration. For example, the conductive neutral layer 206is adjacent to the outer layer 202, the conductive line layer 210 isadjacent to the conductive neutral layer 206, the conductive neutrallayer 208 is adjacent to the conductive line layer 210, and theconductive line layer 212 is adjacent to the conductive neutral layer208 and the outer layer 204. As shown, the conductive line layer 210 issandwiched between the conductive neutral layers 206, 208, and theconductive neutral layer 208 is sandwiched between the conductive linelayers 210, 212. As such, the conductive layers 206, 208, 210, 212 forman alternating configuration of one neutral layer and one line layer.

The alternating configuration of one neutral layer and one line layercan form one or more X-capacitors to suppress differential mode noise,and in turn help reduce EMI. For example, and as shown in FIG. 2B, oneX-capacitor 216 may be formed between the conductive line layer 210 andthe conductive neutral layer 206, and another X-capacitor 218 may beformed between the conductive line layer 212 and the conductive neutrallayer 208. In the particular example of FIG. 2B, the X-capacitor 216 isformed between the side of the conductive line layer 210 adjacent to theconductive neutral layer 208 and the side of the conductive neutrallayer 206 adjacent to the outer layer 202. The X-capacitor 218 is formedbetween the side of the conductive line layer 212 adjacent to the outerlayer 204 and the side of the conductive neutral layer 208 adjacent tothe conductive line layer 210.

As shown in FIG. 3, the multilayer power transmission board 300 includesthe two electrically conductive outer layers 302, 304, three innerelectrically conductive layers 306, 308, 310 positioned between theouter layers 302, 304, and a dielectric medium 312 positioned betweeneach of the conductive layers 302, 304, 306, 308, 310 to electricallyisolate the conductive layers from each other. The dielectric medium 312of FIG. 3 may extend completely around an exterior side of the outerlayers 302, 304 (as shown), may not extend around the exterior side ofthe outer layers 302, 304, etc. Additionally, the conductive outerlayers 302, 304 may provide shielding for the inner conductive layers306, 310, as explained above.

In some examples, the conductive layer 306 of FIG. 3 may be an ACneutral conductor, and the conductive layer 310 of FIG. 3 may be an ACline conductor. In such examples, the conductive layer 306 is aconductive neutral layer and the conductive layer 310 is a conductiveline layer. Therefore, if the multilayer board 300 is employed in thepower supply 100 of FIG. 1, the conductive neutral layer 306 may beelectrically coupled to the connection designated as the neutral powerconnection (e.g., the connection A), and the conductive line layer 310may be electrically coupled to the connection designated as the linepower connection (e.g., the connection B).

When the board 300 is used in the power supply 100 of FIG. 1, theconductive layer 306 is a positive DC conductor, and the conductivelayer 310 is a reference conductor. In such examples, the conductivelayer 306 is electrically coupled to the connection designated as thepositive power connection (e.g., the connection A), and the conductivelayer 310 is electrically coupled to the connection designated as thereference power connection (e.g., the connection B). Alternatively, theconductive layer 306 may be a reference conductor and the conductivelayer 310 may be a positive DC conductor when the board 300 is used inthe power supply 100 of FIG. 1.

As shown in FIG. 3, the conductive layer 308 extends between theconductive layers 306, 310. As such, the conductive layer 308 separatesthe conductive layer 306 and the conductive layer 310. Due to theconductive layer 308 and the layers 302, 304, each conductive layer 306,310 is shielded individually. In other words, each of the two shieldingareas created by the conductive layer 308 and the layers 302, 304shields only one conductive layer in the particular example of FIG. 3.

Although not shown, the conductive layers 202, 204 of FIGS. 2a and 2band/or the conductive layers 302, 304, 308 of FIG. 3 may be coupledtogether via an electrically conductive material, as explained herein.As such, the inner conductive layers 206, 208, 210, 212 of FIGS. 2a and2b and/or the inner conductive layers 306, 310 of FIG. 3 may be at leastpartially shielded, surrounded, enclosed, etc. by conductive layer(s).For example, the conductive layers 302, 304, 308 of FIG. 3 may beelectrically coupled together thereby substantially enclosing theconductive neutral layer 306 and the conductive line layer 310 to shieldthe conductive layers 306, 310, as explained herein. This configurationis similar to a coaxial cable positioned inside another coaxial cable.

Further, the conductive layers 202, 204 of FIGS. 2a and 2b and/or theconductive layers 302, 304, 308 of FIG. 3 may be grounded, as explainedabove (e.g., to provide improved shielding performance, etc.).

FIGS. 4A, 4B and 4C illustrate conductive layers 402, 404, 406 of apower transmission multilayer board that may be used in the power supply100 of FIG. 1 and/or another suitable power supply. The conductive layer406 is an inner conductive layer similar to any one of the conductivelayers 206, 208, 210, 212 of FIGS. 2a and 2b and/or the conductivelayers 306, 310 of FIG. 3. The conductive layers 402, 404 are outerlayers similar to the layers 202, 204 of FIGS. 2 a and 2 b and/or thelayers 302, 304 of FIG. 3. The outer edges of the conductive layers 402,404 extend toward each other and electrically couple together tosubstantially enclose the conductive layer 406 when the layers 402, 404,406 are formed into a multilayer board. This configuration shields theconductive layer 406, as explained above. The outer edges of theconductive layers 402, 404 may be formed by platting an edge of themultilayer board, as further explained below.

The power transmission multilayer boards disclosed herein and the maincircuit boards disclosed herein may be orientated in any suitable mannerrelative to each. For example, and with reference to FIG. 1, themultilayer board 104 may be substantially parallel to the main circuitboard 102, as shown. In other embodiments, the multilayer board 104 maybe substantially perpendicular to the main circuit board 102.

For example, FIGS. 5-7 illustrate a power supply 500 including a maincircuit board 502 and a multilayer power transmission board 504extending in a plane substantially perpendicular to the main circuitboard 502. This perpendicular orientation of the multilayer board 504may save space on the main circuit board 502, as explained herein.Alternatively, the multilayer board 504 may extend in a planesubstantially parallel to the main circuit board 502 without departingfrom the scope of this disclosure.

The multilayer board 504 may include one or more of the multilayercombinations shown in FIGS. 2-4.

As shown in FIGS. 5-7, the power supply 500 includes a power connector510 adjacent one side 506 of the main circuit board 502. In thisparticular example, the power connector 510 includes an AC power inputconnector and a DC power output connector. The AC power input connectorhas a neutral connection and a line connection for coupling to one ormore layers of the multilayer board 504, as explained herein.Alternatively, the power connector 510 may include a DC power inputconnector if desired.

The multilayer power transmission board 504 extends along an edgesurface of the main circuit board 502. For example, in the particularexample shown in FIGS. 5 and 6, the multilayer board 504 is attached tothe main circuit board 502 (e.g., on the edge surface and/or anothersurface of the main circuit board 502), and extends between the side 506of the main circuit board 502 and another side 508 of the main circuitboard 502. As shown, the multilayer board 504 extends substantially thelength of the main circuit board 502. This configuration may provide atleast some structural support for the main circuit board 502 therebypreventing the board 502 from warping, twisting, breaking, etc. due tothe weight of components on the board 502.

Additionally, and as shown in FIGS. 5-7, the power supply 500 includesvarious electrical components 512 disposed on the top surface of themain circuit board 502. The electrical components 512 may include one ormore capacitors, inductors, transformers, power switches, rectificationcircuits, control circuits (e.g., control circuit integrated circuits,etc.), etc. The electrical components 512 of the power supply 500 may beused to form one or more AC/DC converters, DC/DC converters, filters,etc.

For example, an AC/DC converter may be positioned adjacent the side 508of the main circuit board 502. In such examples, the AC/DC converter maybe electrically coupled to layer(s) of the multilayer board 504 toreceive AC input power. The AC/DC converter then outputs DC power to oneor more components 512 on the board, the power connector 510, etc. Forexample, DC power may be provided to one or more DC/DC converters toregulate, increase, decrease, etc. the DC voltage and/or current beforeit is provided to the DC power output connector of the power connector510.

As shown in FIG. 7, the multilayer board 504 includes a power input 514electrically coupled to the AC power input connector of the powerconnector 510. As shown, the main circuit board 502 includes a filter516 electrically coupled between the power connector 510 (e.g., the ACpower input connector) and the power input 514 of the multilayer board504. In the particular example shown in FIGS. 5-7, the filter 516 is acommon mode choke (e.g., a single turn common mode choke, etc.).Alternatively, the filter 516 may include another suitable choke, etc.

The power supplies disclosed herein may be manufactured in any suitablemanner. For example, FIGS. 8A and 8B illustrate a portion of amultilayer power transmission board 800 that may be used in any one ofthe power supplies disclosed herein. The multilayer board 800 mayinclude two or more conductive layers including, for example, outerconductive layers (e.g., outer ground layers, etc.) and inner conductivelayers (e.g., one or more inner ground layers, conductive neutrallayers, conductive line layers, etc.).

As shown in FIG. 8A, two slots 802, 804 are formed in the multilayerpower transmission board 800 to expose at least a portion of an interior806, 808 of the multilayer board 800. For example, the slots 802, 804may be milled out of the multilayer board 800 on opposing sides of theboard. Alternatively, the slots 802, 804 may be formed in the multilayerboard 800 in another suitable manner.

As shown, the slots 802, 804 are defined by the multilayer board 800.For example, and as shown in FIG. 8A, the slots 802, 804 are completelydefined by the multilayer board 800 such that the slots are enclosed bythe board 800. In such examples, the two slots 802, 804 are formedwithin a perimeter of the multilayer board 800. In other embodiments,the slots 802, 804 may be at least partially defined by the multilayerboard 800.

The exposed interior 806, 808 of the multilayer board 800 is then platedwith a conductive material. For example, the conductive ground layers ofthe multilayer board 800 may extend to an outer periphery (e.g., anouter perimeter 814, an area adjacent the outer perimeter 814, etc.) ofthe multilayer board 800. As such, after the slots 802, 804 are formed,the conductive ground layers are exposed along the interior 806, 808 ofthe multilayer board 800. Thus, when the conductive material is platedon the multilayer board 800, the conductive material makes contact with,and therefore electrically couples together, the inner and/or outerconductive ground layers of the multilayer board 800.

As shown in FIG. 8A, this conductive material may plate the entireexposed interior 806, 808 of the multilayer board 800. In otherembodiments, the conductive material may plate only portions (e.g., aninner side) of the exposed interior 806, 808 of the multilayer board 800if desired.

In the particular example of FIG. 8A, the slots 802, 804 and theconductive material on the exposed interior 806, 808 of the multilayerboard 800 extend continuously across the length of the multilayer board800. For example, the slots 802, 804 may extend continuously fromopposing sides of the board. The conductive material may then plate theentire length of each slot 802, 804. This may ensure the groundedconductive layers (including the plated conductive material)substantially surround the inner conductive layers.

In other embodiments, the inner and/or outer conductive layers (e.g.,ground layers) of the multilayer board 800 may be electrically coupledtogether in another suitable manner. For example, FIG. 9 illustrates aportion of a multilayer power transmission board 900 including slots902, 904 substantially similar to the slots 802, 804 of FIG. 8A. Themultilayer board 900 of FIG. 9, however, includes vias 906 extendingbetween surfaces of the board. The vias 906 are plated with a conductivematerial that makes contact with, and therefore electrically couplestogether, the inner and/or outer conductive layers (e.g., ground layers)of the multilayer board 900, as explained above.

As shown in FIG. 9, the board 900 includes two rows of vias 906 on eachside of the board 900. In other embodiments, more or less rows of viasmay be employed if desired. Additionally, the rows of plated vias mayextend substantially the entire length of the board 900 to ensure theelectrically coupled conductive layers and the vias 906 substantiallysurround the inner conductive power layers, as explained above.

Referring to FIGS. 8 and 9, the multilayer boards 800, 900 of FIGS. 8and 9 each may be electrically coupled to a main circuit board of thepower supply. Preferably, this occurs after the slots 802, 804 areformed and plated. For example, a portion of the plated conductivematerial (e.g., along the exposed surface of the board 800, the vias906, etc.) may contact a ground trace, etc. on the main circuit board(e.g., the main circuit board 102 of FIG. 1). In some embodiments, oneor more conductive connections may be used to physically attach andelectrically couple the multilayer boards 800, 900 to main circuitboards.

In some embodiments, one or more portions of the multilayer board 800,900 of FIGS. 8 and 9 may be removed. For example, and as shown in FIG.8A, side portions 810, end portions 812, etc. between the slots 802, 804and the perimeter 814 of the multilayer board 800 may remain after theslots 802, 804 are formed. These portions 810, 812 may be removed (e.g.,cut, broke, etc. off at a mouse bite, break points, etc.) to expose theplated interior 806, 808, as shown in the multilayer board 800 of FIG.8B. The multilayer board 900 of FIG. 9 includes similar removable sideportions, end portions, etc.

FIG. 10 illustrates a graph 1000 of conducted EMI (dBpV) in a powersupply ranging from about 150 kHz to about 30 MHz. In this particularexample, the power supply includes a main board, a multilayer boardextending across the length of the main board, and an EMI filterpositioned on an opposing side of the main board relative to aninput/output power connector. The multilayer board, however, does notinclude outer conductive ground layers coupled together, as explainedherein. This power supply configuration allows conductive AC power linesin the multilayer board to pick-up electrical noise/magnetic noise fromelectrical components (e.g., switching power converters, DC-DCtransformers, etc.), which are positioned on the main board adjacent tothe multilayer board. This causes the conducted EMI in the power supplyto rise above Class A international limits (represented by lines 1002,1004), as shown in the graph 1000.

FIG. 11 illustrates a graph 1100 of the radiated EMI (dBpV/m) rangingfrom about 30 MHz to about 1 GHz in the power supply explained abovewith reference to FIG. 10. As shown, the radiated EMI exceeds Class Ainternational limits (represented by line 1104).

FIG. 12 illustrates a graph 1200 of conducted EMI (dBpV) in the powersupply 500 of FIGS. 5-7, and FIG. 13 illustrates a graph 1300 of theradiated EMI (dBpV/m) in the power supply 500. As shown, the conductedand radiated EMI in the power supply 500 are reduced compared to theconducted and radiated EMI in the power supply explained above withreference to FIGS. 10 and 11. Additionally, and as shown in FIGS. 12 and13, the conducted EMI in the power supply 500 remains below Class Ainternational limits (represented by lines 1202, 1204 in the graph1200), and the radiated EMI in the power supply 500 remains below ClassA international limits (represented by lines 1302 in the graph 1300).

The conductive layers and/or conductive material disclosed herein mayinclude any suitable electrically conductive material. For example, theconductive layers and/or conductive material may include electricallyconductive metallic materials (e.g., copper, aluminum, gold, silver,etc. and alloys thereof), etc. The dielectric medium disclosed hereinmay include any suitable electrical insulator material such asporcelain, glass, epoxy, plastic, etc. and/or a combination thereof.

Although the multilayer boards disclosed herein are described and/orshown to include a specific number of conductive layers (e.g., outerconductive layers, inner conductive layers, etc.), it should be apparentto those skilled in the art that more or less conductive layers may beemployed without departing from the scope of the disclosure.

The multilayer boards may be used in various different power suppliesincluding, for example, AC/DC power supplies, DC/DC power supplies, etc.For example, any one of the multilayer boards may be employed in a 3 kWAC/DC power supply for providing power (e.g., 12V/246A) to one or moreelectronic devices. The power supplies may include, for example, one ormore power converters having any suitable topology.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A power supply comprising: a main circuit board;and a multilayer power transmission board electrically coupled to themain circuit board, the multilayer board including: a conductive neutrallayer having an inner side; a conductive line layer having an inner sidefacing the inner side of the conductive neutral layer; a dielectricmedium positioned between the conductive neutral layer and theconductive line layer; a first conductive outer layer positionedadjacently to an outer side of the conductive neutral layer; a secondconductive outer layer positioned adjacently to an outer side of theconductive line layer; a conductive plating material positioned within aslot formed in the multilayer power transmission board and covering aninterior portion of the multilayer power transmission board facing theslot; and wherein the conductive plating material electrically couplesthe first and second conductive outer layers.
 2. The power supply ofclaim 1, wherein the multilayer power transmission board extends in aplane perpendicular to the main circuit board.
 3. The power supply ofclaim 1, wherein the main circuit board comprises: an AC power inputconnector; and a filter electrically coupled between the AC power inputconnector and the power transmission multilayer board.
 4. The powersupply of claim 1, wherein the main circuit board comprises: an AC powerinput connector; and a power output connector adjacent to the AC powerinput connector.
 5. The power supply of claim 4, wherein the poweroutput connector includes a DC power output connector.
 6. The powersupply of claim 1, further comprising an X-capacitance formed betweenthe conductive line layer and the conductive neutral layer to suppressnoise in the power supply when AC power is transmitted from one area ofthe main circuit board to another area of the main circuit board.
 7. Thepower supply of claim 6, wherein the first and second conductive outerlayers are grounded.
 8. The power supply of claim 1, wherein the maincircuit board includes a first side and a second side opposing the firstside, and wherein said one area of the main circuit board is adjacent tothe first side of the main circuit board and said other area of the maincircuit board is adjacent to the second side of the main circuit board.9. The power supply of claim 1 further comprising a conductive innerlayer positioned between the conductive line layer and the conductiveneutral layer.
 10. A power assembly comprising: a multilayer powertransmission board comprising: a pair of conductive outer layers; aconductive neutral layer positioned between the pair of conductive outerlayers and having an inner side and an outer side; a conductive linelayer positioned between the pair of conductive outer layers and havingan inner side facing the inner side of the conductive neutral layer andhaving an outer side; a dielectric medium positioned between theconductive neutral layer and the conductive line layer; and a conductivematerial electrically coupling the pair of conductive outer layerstogether and plated on an interior portion of the multilayer powertransmission board within a slot formed in the multilayer powertransmission board.
 11. The power assembly of claim 10 furthercomprising a main circuit board electrically coupled to the multilayerpower transmission board.
 12. The power assembly of claim 11, whereinthe main circuit board comprises a power input connector; and furthercomprising a filter electrically coupled between the power inputconnector and the multilayer power transmission board.
 13. The powerassembly of claim 11 further comprising an X-capacitance formed betweenthe conductive line layer and the conductive neutral layer to suppressnoise in the power supply when AC power is transmitted from one area ofthe main circuit board to another area of the main circuit board. 14.The power assembly of claim 10 further comprising an inner conductivelayers positioned between the conductive neutral layer and theconductive line layer.
 15. The power assembly of claim 14, wherein innerconductive layer is coupled to the pair of conductive outer layers viathe conductive material.
 16. The power assembly of claim 15, whereinconductive material is grounded.
 17. A method of manufacturing a powersupply including a main circuit board and a power transmissionmultilayer board, the power transmission multilayer board including aconductive neutral layer having an inner side facing the inner side ofthe conductive line layer and having an outer side, a conductive linelayer having an inner side and an outer side, a dielectric mediumpositioned between the conductive neutral layer and the conductive linelayer, a first conductive ground layer positioned adjacently to theouter side of the conductive neutral layer, and a second conductiveground layer positioned adjacently to the outer side of the conductiveline layer, the method comprising: forming at least two slots in thepower transmission multilayer board to expose at least a portion of aninterior of the power transmission multilayer board; plating with aconductive material the exposed interior of the power transmissionmultilayer board so that the conductive material is in contact with thetwo conductive ground layers; and electrically coupling the powertransmission multilayer board and the main circuit board.
 18. The methodof claim 17, wherein forming the at least two slots includes forming theat least two slots within a perimeter of the power transmissionmultilayer board.
 19. The method of claim 18 further comprising removinga portion of the power transmission multilayer board between each of theat least two slots and the perimeter of the power transmissionmultilayer board.
 20. The method of claim 19, wherein the powertransmission multilayer board includes another conductive ground layerpositioned between the conductive neutral layer and the conductive linelayer, and wherein plating with the conductive material includes platingwith the conductive material so that the conductive material is incontact with the other conductive ground layer.